mysterious death of cory monteith. It will take coroners several days to complete the autopsy. We'll learn how "glee" will go on without him. Neal karlinsky has the new details from vancouver. Good morning, neal. Reporter: George, good morning. We're outside the hotel where cory monteith died this weekend. And look at this. The wall of flowers in tribute continues to grow. That, as family and friends just try to grapple with how he died. How could a 31-year-old, very fit and seemingly healthy man suddenly die, alone in his hotel room? This morning, the mystery of cory monteith's death is being closely examined by investigators. Interviewing his friends and trying to get a sense of his state of mind in the days leading up to his death. He'll be very in depth and very thorough in our investigation, to determine if it was natural causes of death or something else that possibly led to that death. Reporter: A statement from the coroner's office, which is heading up the investigation, says there was no obvious cause of death noted upon initial examination at the scene. Adding that toxicology testing is necessary for the determination of the cause and classification of death. That's because monteith struggles with addiction. Even a recent stint in rehab are well-known to investigators. When I was a kid, I struggled a lot with who I was and where my life was going. Reporter: Monteith reportedly borrowed from his past for his final movie role, playing a drug-addicted hustler in a gritty and yet-to-be released independent film called "mechanic." &#9834; I know it's late I know you're weary &#9834; Reporter: Meantime, producers of "glee," the show that relied on monteith, had been prepared to shoot fresh scenes with him for the new season in just weeks, with a large story line for him specifically. Can "glee" move on through this? Yes. But I think it does so with a giant hole. Cory's character was not only a big piece of that ensemble. But he was also the sort of heart and anchor of the show. Reporter: How they deal with monteith's death will weigh heavily on the show. And also be part of the legacy of a talented, young man. What family and friends are waiting for now are the toxicology report to determine if drugs were in his system at the time of his death or if this was something else. Those should take several days, at least, according to investigators.

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